Long-term acute-care (LTAC) hospitals are facilities exempt from the Medicare prospective payment system and which provide care to patients suffering from prolonged critical illness. From August 1, 1995 to July 31, 1996, we studied the outcomes of 133 mechanically ventilated patients who were consecutively admitted to a large urban LTAC hospital from intensive care units (ICUs) of acute-care hospitals. Survival and functional status within 1 yr after the index admission were measured, and specific patient variables were used to develop a predictive model for survival at 1 yr. Of the 133 patients studied, 66 (50%) died prior to discharge. Of discharged patients, 70% had been successfully liberated from mechanical ventilation. One year after LTAC hospital admission, 103 (77%) of the patients had expired, typically after spending the majority of their days in acute care or long-term care facilities. Eleven 1-yr survivors (8%) were fully functional, whereas the remainder had significantly reduced functional status. Patients older than 74 yr, and patients older than 64 yr and not functionally independent before admission, had a 95% (confidence interval [CI]: 84% to 99%) 1-yr mortality; patients without these characteristics had a 56% (CI: 41% to 71%) 1-yr mortality (p < 0.001). We demonstrate characteristics predicting the poorest prognoses for patients requiring prolonged mechanical ventilation. These characteristics may be identifiable before transfer to an LTAC hospital.